Related papers: Light-by-light scattering in SANC
This is a short review of some hard two-photon processes: $\\ a) \,\,\gamma\gamma\to {\overline P}_1 P_2,\,\, {\overline P}_1 P_2= \{\pi^+\pi^-, K^+ K^-, K_S K_S, \pi^o\pi^o, \pi^o\eta\}\,, \\ b) \,\,\gamma\gamma\to V_1 V_2,\,\, V_1…
Dramatic progress has been made over the last decade in the numerical study of quantum chromodynamics (QCD) through the use of improved formulations of QCD on the lattice (improved actions), the development of new algorithms and the rapid…
I summarize recent progress in lattice gauge theory, with particular emphasis on results from numerical simulations. A major success has been the determination of the light hadron spectrum in the quenched approximation with sufficient…
I apply a recently developed algorithm for reweighting simulations of lattice QCD from one quark mass to another to simulations performed with overlap fermions in the epsilon regime. I test it by computing the condensate from distributions…
We present a theoretical study of the $\gamma\gamma^{*} \to \pi^+\pi^-, \pi^0\pi^0$ processes from the threshold through the $f_2(1270)$ region in the $\pi\pi$ invariant mass. We adopt the Omn\`es representation in order to account for…
Dynamical mass generation in a three-dimensional version of finite-temperature QED is studied with the help of Schwinger-Dyson equations in the real-time formalism. We go beyond the bare-vertex approximation and include wave-function…
We briefly review the status of the calculation of next-to-next-to-leading order corrections to large angle Bhabha scattering in pure QED. In particular, we focus on the analytic calculation of the two-loop virtual corrections involving a…
We present a lattice simulation study of large $N_c$ regularities of meson and baryon spectroscopy in $SU(N_c)$ gauge theory with two flavors of dynamical fundamental representation fermions. Systems investigated include $N_c=2$, 3, 4, and…
We extend the generalized D-dimensional unitarity method for numerical evaluation of one-loop amplitudes by incorporating massive particles. The issues related to extending the spinor algebra to higher dimensions, treatment of external…
With the ongoing experimental interest in exploring the excited hadron spectrum, evaluations of the matrix elements describing the formation and decay of such states via radiative processes provide us with an important connection between…
The standard S-matrix formulation cannot generally be used in the treatment of atomic scattering processes, involving bound-state QED effects, due to the special type of singularity that can here appear. This type of singularity can be…
The combination of energetic electron beams, delivered from conventional accelerators at a high repetition rate, and ultraintense lasers, makes it possible to perform precision measurements of strong-field QED. The LUXE collaboration aims…
The possibility of treating colour in one-loop amplitude calculations alike the other quantum numbers is briefly discussed for semi-numerical algorithms based on generalized unitarity and parametric integration techniques. Numerical results…
Hamiltonian light-front quantum field theory provides a framework for calculating both static and dynamic properties of strongly interacting relativistic systems. Invariant masses, correlated parton amplitudes and time-dependent scattering…
In this paper, we present an improvement of a method for computing scattering amplitudes that include external (polarized) fermions with the following features: the formulas are quite general and work for different kinematic configurations…
QCD at non-zero chemical potential ($\mu$) for quark number has a complex fermion determinant and thus standard simulation methods for lattice QCD cannot be applied. We therefore simulate this theory using the Complex-Langevin algorithm…
In this paper we present a numerical implementation of the one-loop QED corrections to the hard-bremsstrahlung process e- e+ \to e- e+ gamma. These corrections can be included in the Monte Carlo event generators employed for simulating…
Motivated by various excesses observed by the Fermi-LAT and AMS collaborations, we perform a detailed analysis of QCD uncertainties on particle spectra from dark-matter annihilation (or decay) into jets. When annihilated to SM particles,…
I discuss a formalism for computing quantum scattering amplitudes using a semiclassical expansion of a functional integral representation for the S-matrix. The classical background for the expansion is determined by solving the equations of…
We present a method for symbolic calculation of Feynman amplitudes for processes involving both massless and massive fermions. With this approach fermion strings in a specific amplitude can be easily evaluated and expressed as basic Lorentz…